From: John Hubbard <jhubbard@nvidia.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>, Xu Yilun <yilun.xu@intel.com>,
Wu Hao <hao.wu@intel.com>, Moritz Fischer <mdf@kernel.org>,
<linux-fpga@vger.kernel.org>
Subject: [PATCH v3] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages()
Date: Mon, 25 May 2020 15:17:54 -0700 [thread overview]
Message-ID: <20200525221754.433023-1-jhubbard@nvidia.com> (raw)
This code was using get_user_pages_fast(), in a "Case 2" scenario
(DMA/RDMA), using the categorization from [1]. That means that it's
time to convert the get_user_pages_fast() + put_page() calls to
pin_user_pages_fast() + unpin_user_pages() calls.
There is some helpful background in [2]: basically, this is a small
part of fixing a long-standing disconnect between pinning pages, and
file systems' use of those pages.
[1] Documentation/core-api/pin_user_pages.rst
[2] "Explicit pinning of user-space pages":
https://lwn.net/Articles/807108/
Cc: Xu Yilun <yilun.xu@intel.com>
Cc: Wu Hao <hao.wu@intel.com>
Cc: Moritz Fischer <mdf@kernel.org>
Cc: linux-fpga@vger.kernel.org
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
Hi,
This is the same logical change as in v2, but it is applied to
char-misc-next, in order to avoid a merge problem with Souptick's
commit c9d7e3da1f3c ("fpga: dfl: afu: Corrected error handling levels <Souptick Joarder>")
thanks,
John Hubbard
NVIDIA
drivers/fpga/dfl-afu-dma-region.c | 19 +++++--------------
1 file changed, 5 insertions(+), 14 deletions(-)
diff --git a/drivers/fpga/dfl-afu-dma-region.c b/drivers/fpga/dfl-afu-dma-region.c
index 5942343a5d6e..0b817b722920 100644
--- a/drivers/fpga/dfl-afu-dma-region.c
+++ b/drivers/fpga/dfl-afu-dma-region.c
@@ -16,15 +16,6 @@
#include "dfl-afu.h"
-static void put_all_pages(struct page **pages, int npages)
-{
- int i;
-
- for (i = 0; i < npages; i++)
- if (pages[i])
- put_page(pages[i]);
-}
-
void afu_dma_region_init(struct dfl_feature_platform_data *pdata)
{
struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata);
@@ -57,22 +48,22 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
goto unlock_vm;
}
- pinned = get_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
+ pinned = pin_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
region->pages);
if (pinned < 0) {
ret = pinned;
goto free_pages;
} else if (pinned != npages) {
ret = -EFAULT;
- goto put_pages;
+ goto unpin_pages;
}
dev_dbg(dev, "%d pages pinned\n", pinned);
return 0;
-put_pages:
- put_all_pages(region->pages, pinned);
+unpin_pages:
+ unpin_user_pages(region->pages, pinned);
free_pages:
kfree(region->pages);
unlock_vm:
@@ -94,7 +85,7 @@ static void afu_dma_unpin_pages(struct dfl_feature_platform_data *pdata,
long npages = region->length >> PAGE_SHIFT;
struct device *dev = &pdata->dev->dev;
- put_all_pages(region->pages, npages);
+ unpin_user_pages(region->pages, npages);
kfree(region->pages);
account_locked_vm(current->mm, npages, false);
--
2.26.2
next reply other threads:[~2020-05-25 22:17 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-25 22:17 John Hubbard [this message]
2020-05-27 0:10 ` [PATCH v3] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages() Wu, Hao
2020-05-31 21:27 ` Moritz Fischer
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